This is a core clinical/microbiology facility which will interact with the behavioral and epidemiological studies and with the basic science as well as with other NIH supported research in Dr. Sparling's lab, which is not explicitly described in this proposal. The core will serve to link the arenas of epidemiology and behavioral science with those of microbiology and immunology. In particular, activities supported by this core will help to determine whether there is strain specific immunity in mucosal gonococcal infection. Identification of strains will be expanded to include restriction fragment length polymorphisms, in addition to auxotype and serotype. A total of 1500 gonococci will be typed by these techniques. Strain typing data also will be important to determination of sexual networks in the population studied in Project 6. The core will serve as a repository for serum and mucosal antibody specimens collected on clients seen at the Wilson County and Wake County STD Clinics and also for serum samples obtained from volunteers in the human inoculation studies describe in Project 3. These samples will be made available to investigators on basic science projects in this Center as well as other investigators at other institutions.